1. Field of the Invention
The present invention relates to an electron emitter comprising a cathode electrode and an anode electrode which are formed on an electric field receiving member, a method of driving the electron emitter, a display employing the electron emitter, and a method of driving the display.
2. Description of the Related Art
Recently, electron emitters having a cathode electrode and an anode electrode have been used in various applications such as field emission displays (FEDs) and backlight units. In an FED, a plurality of electron emitters are arranged in a two-dimensional array, and a plurality of fluorescent bodies are positioned in association with the respective electron emitters with a predetermined gap therebetween.
Conventional electron emitters are disclosed in Japanese laid-open patent publication No. 1-311533, Japanese laid-open patent publication No. 7-147131, Japanese laid-open patent publication No. 2000-285801, Japanese patent publication No. 46-20944, and Japanese patent publication No. 44-26125, for example. All of these disclosed electron emitters are disadvantageous in that since no dielectric body is employed in the electric field receiving member, a forming process or a micromachining process is required between facing electrodes, a high voltage needs to be applied to emit electrons, and a panel fabrication process is complex and entails a high panel fabrication cost.
It has been considered to make an electric field receiving member of a dielectric material. However, though various theories have been presented in documents 1 through 3, shown below, about the emission of electrons from a dielectric material, the principles behind an emission of electrons have not yet been established, and advantages of an electron emitter having an electric field receiving member made of a dielectric material have not been achieved.
[Documents]
1. Yasuoka and Ishii, “Pulse electron source using a ferrodielectric cathode”, Japanese J. Appl. Phys., Vol. 68, No. 5, p. 546-550 (1999).
2. V. F. Puchkarev, G. A. Mesyats, On the mechanism of emission from the ferroelectric ceramic cathode, J. Appl. Phys., Vol. 78, No. 9, 1 Nov. 1995, p. 5633-5637.
3. H. Riege, Electron emission ferroelectrics—a review, Nucl. Instr. and Meth. A340, p. 80-89 (1994).
The conventional electron emitters do not have a good straightness of electron emission, i.e., a good ability to cause emitted electrons to travel straight to a given object (e.g., a fluorescent body). In order to achieve a desired current density with electrons, it is necessary to apply a relatively high voltage to the electron emitter.
If conventional electron emitters are applied to a display, then the crosstalk is relatively large because the straightness of electron emission is not good. Specifically, electrons emitted from an electron emitter are highly likely to be applied to a fluorescent body positioned adjacent to the fluorescent body corresponding to the electron emitter from which the electrons have been emitted. As a result, it is difficult to reduce the pitch of the fluorescent bodies.
Most displays which incorporate conventional electron emitters are digitally controlled to either emit or not emit electrons. Those displays are not based on the idea of analog control over the amount and acceleration of electrons that are emitted from electric field receiving members, and fail to control finely divided gradations.